Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, non-destructive and open-world behavior, so the lower bar applies. The description nonetheless adds real operational context: newest-first ordering, that distance/duration keep Garmin's native units (no conversion), that identifiers and GPS fields are stripped from results, and that activity names/descriptions must be treated as untrusted text. That last point is a security-relevant disclosure an agent would otherwise not know.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences/lines, zero filler, with the core operation and ordering front-loaded and supporting caveats after. Every sentence adds distinct information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Output schema exists, so return values need not be described, and the description covers ordering, unit conventions, field redaction, and text-safety. Remaining gaps are minor: date format, whether end_date is inclusive, and what 'search' matches against.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the full burden, and it only names the filter categories ('dates, sport or text', 'start/limit') without mapping them to start_date/end_date, activity_type/activity_subtype, or search, and without stating the date string format or the 100-item limit cap. It confirms the general purpose of each parameter group but leaves the specifics to the bare schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List activities') plus ordering ('newest first') and the three filter axes plus pagination. It does not explicitly differentiate from the singular sibling garmin_activity, but the 'list vs. single activity' distinction is inferable from the name and plural framing.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Filtering and pagination options imply when the tool is useful, but there is no explicit guidance on when to prefer it over garmin_activity or the metrics siblings, and no statement of defaults or limits. Usage is implied rather than directed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare this as a safe, idempotent read operation. The description adds useful behavioral context that common GPS fields are removed, which is important for an agent interpreting the returned data. It does not cover permission requirements or error behavior, but those are less critical here.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, front-loaded sentence with no wasted wording. It covers the operation, returned data, and a key caveat in compact form.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the low complexity, existing output schema, and safety annotations, the description covers the essential content and the GPS-field omission. The main missing piece is guidance on sourcing the activity_id parameter, which slightly limits completeness.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The single required activity_id parameter has 0% schema description coverage, so the description must compensate. It only implies that the integer identifies 'an activity' and does not explain how to obtain or format the activity ID, leaving a meaningful gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific read operation on a single activity and enumerates the returned content: summary, measurements, and splits. It also distinguishes itself from the plural garmin_activities sibling by being explicitly singular and detail-oriented.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit guidance on when to use this tool versus garmin_activities or garmin_activity_workouts. The singular name and 'an activity's' wording imply per-activity detail, but no alternative, prerequisite, or exclusion is stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so 'Changes nothing' merely restates structured metadata and adds no new information. Nothing is said about behavior when an activity has no associated workout (empty result vs. error) or about any retrieval constraints, leaving the behavioral picture thin.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the core action, with no filler text. The second sentence is largely redundant against the annotations, which slightly reduces the value of the phrasing but not its brevity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need no explanation, and the single simple parameter plus rich annotations mean little else is required. The only real gap is the absence of any note on the no-workout case or linkage to sibling activity tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% for the single activity_id parameter, so the schema offers only a type and bounds. The description partially compensates by framing the parameter as an identifier for a 'recorded activity,' but it adds no detail on format, source, or validity beyond that.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: 'Read structured workout steps associated with a recorded activity.' This clearly distinguishes it from generic siblings like garmin_activity or garmin_activities, which cover activity data rather than workout steps. It stops short of naming a sibling alternative, but the resource is specific enough to route correctly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent can infer it should call this when it needs the structured workout steps for a known activity_id. There is no explicit when-to-use or when-not-to-use guidance, and no mention of how it relates to garmin_activity, which is the nearest alternative.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare this as a read-only, idempotent, non-destructive operation. The description adds useful behavior not in the annotations: a 90-day maximum range and that samples are omitted by default. It does not mention authentication or rate limits, but those are less critical given the annotations and output schema.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the core purpose and followed by the most important usage distinction. No wasted language.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The output schema and annotations cover return data and safety behavior, and the description covers date range and sample inclusion adequately. However, for a four-parameter tool with 0% schema description coverage, the unexplained intervals_per_day parameter leaves a clear completeness gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It clarifies include_samples via the 'samples are omitted' statement and adds a 90-day cap for the date range, but it never explains intervals_per_day, leaving a meaningful parameter undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: read Body Battery charged/drained values and optional time series. It also distinguishes this tool from the sibling garmin_daily_summary by reserving daily lowest/highest values for that sibling.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It explicitly directs the agent to daily_summary for daily lowest/highest values, which is a clear alternative-selection rule. It also notes that samples are omitted by default, but it does not cover when not to use this tool or other relevant sibling distinctions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only, idempotent, non-destructive, so the description's real contribution is the explicit 'does not contact Garmin' claim, which tells the agent this is a local config read with no network side effects or auth round-trip. It does not describe failure cases (e.g., what a report looks like when no key is configured), which the output schema presumably covers.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, tightly front-loaded: what is reported first, scope caveat second. Nothing redundant, nothing padded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present and annotations covering the safety profile, the description needs only to say what is reported and that no remote call occurs — both are stated. A brief note that this is the recommended first call before the data-fetching siblings would make it complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Zero parameters, so there is no parameter semantics to explain; the baseline of 4 applies. The description correctly adds no noise about arguments.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and the exact facts reported: demo/live mode and whether a local key is configured. The added 'Does not contact Garmin' scopes the tool apart from the data-fetching siblings, though it never explicitly frames itself as the pre-flight/config check for the integration.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit when-to-use or when-not-to-use statement; the agent must infer that this is a cheap pre-call check before invoking garmin_daily_metrics, garmin_sleep, etc. The 'does not contact Garmin' line implies it is safe/cheap to call freely, but that is inference, not guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare the tool read-only, idempotent, non-destructive, and open-world, so safety is covered. The description adds useful behavior beyond annotations: the 1–90 day range limit, the seven-day segmentation constraint, explicit segment dates, and that response shapes/units come from Garmin.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is short and front-loaded, leading with the core action and scope before enumerating metrics and response notes. Every sentence adds information about range limits, segmentation, or response provenance.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained. However, for a required 3-parameter tool with 0% schema descriptions, the description should clarify whether the seven-day segmentation is enforced by the tool or must be handled by the caller, and it should set expectations for large ranges. The current text is adequate but leaves this operational ambiguity unresolved.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It lists the metric values matching the enum and clarifies the date range (1–90 inclusive days) and seven-day segmentation, which adds real meaning for the date parameters. It does not explain whether segmentation is automatic or caller-driven, leaving some ambiguity.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a clear verb ('Read daily trends') and scope (1–90 days) and enumerates the exact metric categories, which lets an agent map it to the correct data domain. It does not explicitly distinguish itself from metric-specific siblings like garmin_sleep or garmin_hrv, so an agent could still be unsure when this aggregator is preferred.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies multi-day trend retrieval and the seven-day segmentation constraint implies batching behavior, but it never says when to use this tool instead of garmin_sleep, garmin_hrv, garmin_daily_summary, or other siblings. There are no explicit exclusions or alternative routing rules.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent and non-destructive, so safety is covered. The description adds a genuinely useful behavioral caveat: results are limited to what Garmin has actually synced for that day, telling the agent that missing metrics mean unsynced, not absent — a real interpretation aid beyond structured fields.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with the resource and its contents, then the scoping caveat. Minimal waste, though 'and more' is vague filler that costs a little precision.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return shape needn't be explained, and the description covers scope plus the day/sync constraint. What remains unaddressed is sibling differentiation, but for a simple one-param read tool this is otherwise complete.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% and only 'day' exists with format=date, so the description must carry the semantics. It does: 'explicit local calendar day' clarifies that the value is a local (not UTC) calendar date that must be provided, which is more than the bare date format conveys.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Names a specific verb (read) and resource (daily health summary) and enumerates the metrics returned (steps, calories, resting HR, stress, Body Battery), so the agent knows what it gets back. It does not differentiate against the very similar siblings garmin_daily_metrics and garmin_health_snapshot, which is the main gap at this level.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

'Includes only measurements Garmin has synced for the explicit local calendar day' implies the preconditions (data must be synced; day is a local calendar date) but never states when to prefer this over garmin_daily_metrics, garmin_health_snapshot, or the per-metric tools like garmin_sleep and garmin_body_battery.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds meaningful behavioral context by clarifying that it returns the latest available estimate as of the given date, which helps interpret cases where no same-day estimate exists.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single front-loaded sentence with no redundant or wasted language. It immediately states the operation and the temporal scope.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter read-only tool with an output schema and strong safety annotations, the description is largely complete. It could mention behavior when no estimate is available, but the output schema can carry return-value details.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There is one required parameter, day, and the schema description coverage is 0%, so the description must carry semantic weight. The phrase 'as of this calendar date' clarifies that day anchors the requested estimate, but it does not add details beyond the schema's date format or explain timezone/future-date behavior.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb and resource: read Garmin's latest fitness-age estimate. It does not explicitly distinguish this tool from sibling Garmin metrics tools, so it is clear but lacks sibling differentiation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by the stated purpose and the calendar-date framing, but there is no explicit guidance on when to use this tool versus related Garmin health and daily-metric tools. No exclusions or alternatives are mentioned.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only/idempotent/open-world, so the description clears the lower bar by adding real context: the call performs four underlying reads and a missing or failed section is reported separately rather than failing the whole call. It also flags demo-data identification and a no-diagnosis constraint, which are behavioral traits not encoded in any structured field.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Four short, front-loaded clauses with no filler: scope first, failure behavior second, alternative tool third, safety constraints last. Every sentence carries information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need no explanation, and the description covers the non-obvious bits (partial results, demo data, no diagnosis). The only meaningful omission is the semantics of the `day` argument, which matters for a date-scoped call.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter (`day`) with 0% schema description coverage beyond type and format=date. The description says "single-day" but never specifies date format, timezone handling, or whether historical days are supported, so it does not fully compensate for the schema gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

"Read a single-day overview combining daily summary, sleep, HRV and heart rate" gives a specific verb, resource, and explicit composition, immediately separating it from the single-metric siblings like garmin_sleep or garmin_hrv.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

"Prefer individual tools when the user asks for just one metric" is an explicit exclusion that routes to the right alternative. It doesn't name a specific sibling or state a positive trigger beyond "overview", but the selection logic is clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is fully covered elsewhere. The description adds genuine context beyond that by specifying units (bpm) and the shape of returned data (resting/min/max values plus optional timestamped samples), but says nothing about behavior when data is missing for a day or about permissions/auth.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single semicolon-linked sentence with the primary read stated first and the optional flag second. No filler, no redundancy with the schema or annotations.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return-value detail is not required, and annotations cover the safety profile. What is left unaddressed is the meaningful ambiguity for this tool: what `day` means (timezone, historical range) and what happens on a day with no recorded data.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description carries the burden for both parameters. It meaningfully explains include_samples as "timestamped samples," but leaves `day` entirely unelaborated — no timezone, date format, or whether it must be today or can be historical. Partial compensation only.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ("Read") and resource (heart rate) plus the exact metrics returned (resting/min/max in bpm), which distinguishes it from the sibling garmin_heart_rate_zones. It stops short of naming that sibling explicitly, so differentiation requires the agent to infer it from the metric names.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies use for a single day of heart-rate data and hints at the optional samples path, but gives no when-to-use vs when-not guidance and never points to garmin_heart_rate_zones or garmin_daily_summary as alternatives. Usage is inferable but not directed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is clear. The description adds only that sport-specific settings may be included if available, which signals response variability, but does not cover return format, prerequisites, or rate limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single tight sentence with no wasted words. The purpose is front-loaded and the sport-specific caveat is appended efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a no-parameter read tool with an output schema and annotations covering safety, the description gives enough context to call it correctly. It does not mention authentication or Garmin connection prerequisites, but those are likely platform-level concerns handled elsewhere, so the gap is minor.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

There are zero parameters, so parameter semantics are not a concern; the baseline for a no-param tool is 4. The schema has 100% description coverage but contains no properties to document, and the description appropriately does not discuss parameters.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource: 'Read configured heart rate zones', and adds scope with 'including sport-specific settings if available'. The word 'configured' distinguishes it from a live heart-rate reading sibling like garmin_heart_rate, but the description never names or explicitly contrasts with that sibling.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied by 'Read configured heart rate zones' – an agent can infer this is for retrieving zone configuration rather than live heart-rate data. However, there is no explicit when-to-use statement, no exclusion, and no named alternative; guidance remains implicit.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The read-only, idempotent, non-destructive annotations already establish the safety profile, and the description is consistent with them. It adds useful semantic context about what is read (overnight HRV, baseline, status, optional readings), but does not expand on behavior such as handling missing data or response shape beyond what the output schema provides.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The definition is a single front-loaded sentence with no wasted words. The purpose, units, and optional samples behavior are all stated efficiently.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool is simple, has rich annotations, and includes an output schema, so the description is adequate for basic selection. However, the missing explanation of the required 'day' parameter and the lack of usage guidance leave gaps for an agent deciding how to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry parameter meaning. It explains the optional 'include_samples' behavior ('optionally include readings') but leaves the required 'day' parameter unexplained, including its date format and whether it selects the overnight period.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a specific verb ('Read') and resource ('overnight HRV'), plus units and returned components ('baseline and status'). It clearly states what the tool does, though it does not distinguish itself from sibling health tools like garmin_sleep or garmin_daily_metrics.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no explicit guidance on when to use this tool versus alternatives, nor any prerequisites or exclusions. The only implied usage is reading overnight HRV, with no instructions about which sibling to choose for related metrics.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety and idempotency profile is fully covered. The description adds only the scoping constraint (explicit date, presumably single-day, not a range) and says nothing about auth, rate limits, or data availability windows.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler; the resource list comes first and the scoping constraint second, so an agent can stop reading after one line.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, return values need no explanation, and annotations cover safety. For a one-parameter read-only tool the description is nearly sufficient, missing only date format/range guidance.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must carry meaning; it partially does by stressing the date must be explicitly requested, implying no defaulting to today or relative expressions. However it never states the accepted date format or that only one day can be queried, leaving part of the semantic gap open.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb ('Read') and specific resources ('food logs, nutrition totals and goals'), which clearly separates it from the sibling metric tools like garmin_daily_summary and garmin_sleep. It is clear what the tool returns, though it doesn't explicitly name the Garmin/nutrition domain boundary against siblings.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'for an explicitly requested date' implies usage context and warns against relative/ambiguous dates, but there is no explicit when-to-use vs. when-not, nor a pointer to an alternative tool for other nutrition queries. Usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so safety is covered. The description adds the useful fact that metrics are 'available' ones (i.e., partial results are possible) but says nothing about timezone handling, missing-data behavior, or history limits. With annotations carrying safety, a 3 reflects modest added context.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One front-loaded sentence with a clear verb and an enumerated payload; no filler. It is arguably a touch terse given the unaddressed 'day' semantics, but nothing is wasted.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

An output schema exists, so return values need not be explained, and annotations cover safety. Still missing is the one thing an agent must know to call correctly: what calendar day to pass and what happens when no sleep record exists.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The single parameter 'day' has 0% schema description coverage and the description never mentions it, so the critical ambiguity — whether 'day' means the date the sleep started or the wake-up date, and in which timezone — is unresolved. For a one-parameter tool this is the main semantic risk an agent faces.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb (Read) plus resource (sleep) and an enumerated list of the metrics returned: duration, stages, score, respiration. It is clearly distinguishable from siblings like garmin_hrv or garmin_daily_metrics, though it never explicitly states the boundary with those tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to choose this over garmin_daily_summary, garmin_health_snapshot or garmin_hrv, which overlap in reporting overnight data. It also doesn't state prerequisites such as wearing the device overnight or how far back data is available.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered structurally. The description adds the meaningful caveat that availability depends on device support and recording, but says nothing about the shape or granularity of 'acclimation data' or what happens when no data exists (empty vs error).

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with the verb first and no filler. It is efficient, though slightly under-specified rather than over-long.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Because an output schema exists, return values needn't be explained. However, the description leaves 'acclimation' undefined and does not clarify the optional samples parameter, so an agent still lacks enough to invoke the tool optimally.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% and the description mentions no parameters at all. The meaning of 'include_samples' (what samples, at what granularity) and the required 'day' format are left entirely to the bare schema types, which is inadequate compensation for a 0% coverage gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb ('Read') plus a precise resource (daily Pulse Ox/SpO2 and acclimation data), which clearly separates it from siblings like garmin_sleep, garmin_heart_rate and garmin_hrv. It doesn't explicitly name or contrast with any sibling, but the resource is distinctive enough that an agent won't confuse it.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The clause 'if supported and recorded by the device' gives a useful pre-condition hint that the call may return empty on unsupported hardware, but there is no explicit when-to-use guidance or mention of alternatives (e.g. garmin_health_snapshot for a broader view). Usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.